Is it normal to be indecisive about my major/career?

First I wanted to be a dental hygienist...Then it was public relations....then it was cosmetology...now I just don't know! I just want to make sure I love what I do and it will be a great career. I don't want to end up in a situation where i regret waisting time in school and not liking my career of choice. Is it normal that I can't decide? I'm 21 and I'm afraid if i don't figure out now, I will be doomed.